Electromagnetic overload circuit breaker



Jan. 18,1938. w. LEYHAUSEN ELECTROMAGNETIC OVEHLOAD CIRCUIT BREAKER Filed Dec. 1, 1933 Patented Jan. 18, 1938 ELECTROMAGNETIC OVERLOAD CIRCUIT BREAKER Wilhelm Leyhausen, Nuremberg, Germany Application December 1, 1933, Serial No. 700,579

In Germany October 18, 1933 Claims.

This invention relates to an electro-magnetic overload circuit breaker in which the circuit is broken between the end faces of two magnetic coils, the spark gap being formed by fire-proof 5 partitions which separate the contacts from the coils and protect against flashing over of the breaking spark. Co'nstructions'oi such circuit breakers are already known in-which the release is effected by an armature which is attracted by the two separate magnet coils. The attracting force of the magnet coils is at the same time extremely weak, so that the release can only be causedat a multiple of the nominal current strength.

This objection is overcome by the invention in that, at least one of the magnet coils has a plunger which communicates with the releasing device on the side remote from the magnet coils. Thus, not only a better moment of attraction of the magnet coils and a more rapid operation is obtained, but it also'enables the blowing effect of the coil to be increased in that the coil is provided with a rigid magnetic connection, a yoke or frame, for employing which a separate switching magnet was hitherto required, whereby the device was rendered complicated and expensive.

Two embodiments of the invention are illustrated by way of example in the accompanying 3 drawing in which:

Fig. 1 shows the circuit breaker partly in side coil d is provided with a plunger 1. This latter is connected to a bell-crank lever g the free end of which canact upon the switching mechanism h. The connection between the switching -mechanism and the contacts has been omitted from the drawing for the sake of clearness. In the switching in position the contacts a and b touch one another. If the current exceeds a certain strength, the plunger f is attracted causing the bell crank lever g to strike against the switching mechanisms whereby the switch is moved into the cutting out position. The are forming between the contacts is extinguished by the magnet coils. By fitting a spring counteracting the force of attraction of the coil 11 on the plunger f the strength of the switching out current can be regulated in known manner.

In Fig. 2 the iron strap e is extended to form an iron frame 1', which serves at the same time for fixing the system on a base s. Contrary to the form of construction shown in Fig. 1 the bell crank lever g in Fig. 2 is made of iron and one of its arms, to whicn the plunger is fixed, forms a part of the frame 1. In other respects the operation is the same as'that of the form of construction shown in Fig. 1. The frame 1' may be entirely closed and the bell-crank lever g and plunger 1 constructed as illustrated in Fig. 1.

The peculiar arrangement of the coils, contacts and magnetic release requires a special switching mechanism. An advantageous form of construction is shown in Fig. 3 on a switch with two contacts.

The contacts a and b are resiliently mounted on the base s and a contact bridge u is arranged opposite the contacts on a switch bar t.

A toggle lever system consists of a bell crank lever is, p of a-lever l pivotally mounted on a rigid pin n, of two links it, i forming a toggle lever and pivotally connected with each other by a pivot pin 0, the lever arm 72. connected with the arm k of the bell crank lever by a pivot pin m and the lever i with the lever l by a pivot pin 1i. The arm 1) of the bell crank lever is pivoted on a pivot pin n fixed on the switch bar t the lever being pivotally mounted on the pivot pin 0. The arm p of the bell crank lever is influenced by a spring q and pressed against an abutment w. m

If a switch lever a is swung in clockwise direction, a pin a: eccentrically mounted on the switch lever 2 acts on the lever -Z and brings the lever system into the switching in position shown in dotted lines. I

During this movement the pivot pin 0 of the toggle lever h, 1 moves in a straight line and always at the same distance from the bell crank lever g efiecting the release, so that it always strikes against the lever h in thesame position and with the same force in the event of short- In the circuit.

present instance the device is of particular importance because the movement of the releasing lever can be limited to the smallest size so that the switching speed is increased and the magnet parts can be placed in the most favorable position from the outset.

In order to attain the rectilineal movement of the pivot pin 0, the levers k and Z are of the same length and also the two links it and i of the toggle lever. During the switching in movement the pivot pin m must therefore approach and move away from the engaging surface of the releasing lever g in the same proportion as the pivot pin 12' moves away from and approaches the same. Thus, by differently dimensioning and mounting the levers k and l, the device can be constructed so that the pivot pin 0, during the switching in operation changes its distance from the releasing lever g to a predetermined extent, being desirable in certain instances.

The bell crank lever is, p is also of particular importance forthe device. By suitably shaping and arranging the same the horizontal movement of the toggle lever h, i can impart a vertical movement to the switch bar i, so that the switch may be of compact construction and space and material is saved.

The automatic breaking of the circuit is effected as follows. The device is shown in circuit closing position by dotted lines in Fig. 3. If a short-circuit or an overload occurs, the lever o presses against the pivot pin 0. The toggle lever h, iis thereby bent, and the bell crank lever is, p,

swings under the pressure of spring q, thereby lifting the switch bar t and causing contact bridge u to lift from contacts aand b and break the At the same moment the coil of is cleanergized so that the lever 9 may return to its position of rest. The toggle lever h, i may hence return to its alined position under the force of its own weight, so that the position of the individual parts is now that shown in Fig. 3 in straight lines, that is, in open circuit position.

This is permitted because the resetting lever z is normally in position shown by full lines and the arm b can thus freely swing to the right and offers no substantial resistance to the dropping of the pivot. pin 0. With the parts in the full line position, it is merely necessary to move the resetting lever z to the dotted line position whereupon the toggle will push the lever arm k to the left and cause the lever arm 9 to swing downwardly to depress the bar t and bridging contact u so that the latter again bridges the contacts a and b'. The resetting lever 21 may now be swung to full line position, thus leaving all parts ready for the next operation.

Both coils instead of only one may be provided with plungers if a stronger force is necessary for the releasing. The magnet core of the coils may likewise be divided and one part thereof be fixed whereas the other part forms the plunger.

1. In an electro-magnetic overload circuit breaker, magnet coils, contacts between the end faces of the coils, a plunger in one of the magnet coils, a releasing mechanism for opening the contacts, a transfer means between the plunger,

and the release mechanism, said transfer means including a toggle, a pivoted arm linked to one end of the toggle, a bell crank lever connected to the other end of the toggle, and a switch bar fastened to the free end of the said bell crank lever and displaceable crosswise of the axis of the coils.

2. In an electro-magnetic overload circuit breaker, magnet coils, contacts between the'end faces of said coils, a release mechanism consisting of a toggle, an electro-magnetically controlled bell crank for breaking said toggle, one arm of said bell crank lever being connected to be actuated by energization of one of said magnets, a pivoted arm equal in length to the other arm of said bell crank, said pivoted arm and said other arm of said bell crank being connected together by means of said toggle, whereby the joint of the toggle is uniformly distant from the electromagnetically controlled bell crank lever in all positions of the toggle while its arms are in alinement.

3. In an overload circuit breaker, a pair of axially alined and spaced magnet windings, circuit contacts between the adjacent ends of the windings, one of said contacts being fixed and a second of said contacts being movable transversely of the field between said windings, a frame magnetically connecting the remote ends of said windings, a lever having one end pivoted to the frame and projecting upwardly therefrom, a bell crank lgver pivoted at its angle to said frame and having a depending arm, a pair of pivotally jointed links constituting a toggle, said toggle having its ends connected respectively to the first lever and the depending arms of the bell crank lever, a lift rod pivoted to the remaining arm of the bell crank lever and carrying the movable contact, a spring'urging said bell crank lever to move the lift rod to open circuit position, and means actuated by energization of said windings to engage and flex the toggle at its joint.

4. In an overload circuit breaker, a pair of axially alined and spaced magnet windings, circuit contacts between the adjacent ends of the windings, one of said contacts being flxedtand a second of said contacts being movable transversely of the field between said windings, a frame magnetically connecting the remote ends of said windings, a lever having one end pivoted to the frame and projecting upwardly therefrom, a bell crank lever pivoted at its angle to said frame and having a depending arm, a pair of pivotally jointed links constituting a toggle, said toggle having its ends connected respectively to the first lever and the depending arms of the bell crank lever, a lift rod pivoted to the remaining arm of the bell crank leverand carrying the movable contact, a spring urging said bell crank lever to move the lift rod to open circuit position, a second bell crank lever pivoted to said frame and having one arm below the joint of the toggle and its other arm depending across the remote end of one of said windings, and a magnetic core in the last mentioned winding and connected to the depending arm of the second bell crank lever.

5. In an overload circuit breaker, a pair of axially alined and spaced magnet windings, circuit contacts between the adjacent ends of the windings, one of said contacts being fixed and a second of said contacts being movable transversely of the field between said windings, a frame magnetically connecting the remote ends of said windings, a lever having one end pivoted to the frame and projecting upwardly therefrom, a bell crank lever pivoted at its angle to said frame and having a depending arm, a pair of pivotally jointed links constituting a toggle, said toggle having its ends connected respectively to the first lever and the depending arms of the bell crank lever, a lift rod pivoted to the remaining arm of the bell crank lever and carrying the movable contact, a spring urging said bell crank lever to move the lift rod to open circuit position, and means actuatedby energization of said windings to engage and flex the toggle .at its joint, said links being of equal length and the lever arms to which the ends of the toggle is connected being also of equal length.

6. In an overload circuit breaker, a pair of axially alined and spaced magnet windings, circuit contacts between the adjacent ends of the windings, one of said contacts being fixed and a second of said contacts'being movable transversely of the field between said windings, a frame magnetically connecting the remote ends of said windings, a lever having one end'pivoted to the frame and projecting upwardly therefrom,

a bell crank lever pivoted at its angle to said to said frame and having one arm below the joint of the toggle and its other arm depending across the remote end of one of said windings, and a magnetic core in the last mentioned winding and connected to the depending arm of the second bell crank lever, said links being of equal length and the lever arms to which the ends of the toggle is connected being also of equal length.

'7. In an overload circuit breaker, a pair of axially alined and spaced magnet windings, circuit contacts between the adjacent ends of the windings, one, of said. contacts being fixed and a second of said contacts being movable transversely of the field between said windings, a frame magnetically connecting the remote ends of said windings, a lever having one end pivoted to the frame and projecting upwardly therefrom, a bell crank lever pivoted at its angle to said frame and having a depending arm, a pair of pivotally jointed links constituting a toggle, said toggle having its ends connected respectively to the first lever and the depending arms of the bell crank lever, a lift rod pivoted to the remaining arm of the bell crank lever, and carrying the movable contact, a spring urging sail bell crank lever to move the lift rod to open circuit position, means actuated by energization of said windings to engage and flex the toggle at its joint, and a resetting lever pivoted to the frame and provided with a pin for engaging, the first lever to move the same to circuit closing position.

8. In an overload circuit breaker, a pair of axially alined and spaced magnet windings,- circuit contacts between the adjacent ends of the windings, one of. said contacts being fixed and a second of said contacts being movable trans versely of the field between said windings, a frame magnetically connecting the-remote ends of said windings, a lever having one end pivoted to the frame and projectingupwardly therefrom, a bell crank pivoted at its angle to said frame and having a depending arm, a pair of pivotally jointed links constituting a toggle, said toggle having its ends connected respectively to the first lever and the depending arms of the bell crank lever, a lift rod pivoted to the remaining arm of the bell crank lever and carrying the movable contact, a spring urging said bell crank lever to move the lift rod to open circuit position, a second bell crank lever pivoted to said frame and having one arm below the joint of the toggle and its other arm depending across the remote end of one of said windings, a magnetic core in the last mentioned winding and connected to the depending arm of the second ,bell crank lever, and a resetting lever pivoted to the frame and provided with a pin for engaging the first lever to move the same to circuit closing position.

9. In an overload circuit breaker, a pair of axially alined and spaced magnet windings, circuit contacts between the adjacent ends of the windings, one of said contacts being fixed and a second of said contacts being movable transversely of the field between said windings, a frame magnetically connecting the remote ends of said windings, a lever having one end pivoted to the frame and projecting upwardly therefrom, a bell crank lever pivoted at its angle to said frame and having a depending arm, a pair of pivotally jointed links constituting a toggle, said toggle having its ends connected respectively to the first lever and the depending arms of the bell crank lever, a lift rod pivoted to the remaining arm of the bell crank lever and carrying the movable contact, a spring urging said bell crank lever to move the lift rodto open circuit position, means actuated by energization of said windings to engage and fiex the toggle at its joint, said links being of equal length and the lever arms to which the ends of the toggle are connected being also of equal length, and a resetting lever pivoted to the frame and provided with a pin for engaging the first lever to move the same to circuit closing position.

10. In an overload circuit breaker, a pair of axally alined and spaced magnet windings, circuit contacts between the adjacent ends of the windings, one of said contacts being fixed and a second of said contacts being movable transversely of the field between said windings, a frame magnetically connecting the remote ends of said windings, a lever having one end pivoted to the frame and projecting upwardly therefrom, a bell crank lever pivoted at its angle'to said frame and having a depending arm, a pair of pivotally jointed links constituting a toggle, said toggle having its ends connected respectively to the first lever and the depending arms of the bell crank lever, a lift rodipivoted to the remaining arm of the bell crank lever and carrying the movable contact, a spring urging said bell crank lever to move the lift rod to opencircuit position, a second bell crank lever pivoted to said frame and having one arm below the joint of the toggle and its other arm dependng' across, the remote end of one of said windings, a magnetic core in the last mentioned winding and connected to the depending arm of the second bell crank lever, and a resetting lever pivoted to the frame and provided with a pin for engaging the first lever to move the same to circuit closing position.

WILHELM LEYI-IAUSEN. 

